Climate Change

A scientific look at global climate changes.

Welcome to the Weather Underground's new Climate Change page!
We're just getting started, so keep checking back over the next few months for new additions.

	Monthly Feature

About Glaciers

Glaciers exist on all the continents of the world except Australia. Most of the world's glaciers are found near the North and South Poles (for more information about Arctic and Antarctic glaciers, please see our pages on Greenland and Antarctica). A large number of glaciers, however, are found in mid-latitude and tropical regions wherever the right conditions exist.

Glaciers exert a significant influence on a landscape. As glaciers move across the terrain, they pick up rock and debris, carve valleys (see Figure 1), and create landforms. Flowing glaciers erode and scour the ground beneath and to the sides of them. These rivers of ice also pick up boulders, soil, trees, and other debris and carry it along in their flow. Once the glacier begins its retreat, however, this material is deposited wherever the glacier.s ice melts. Kettle lakes are formed when large chunks of ice fall off of retreating glaciers and melt, filling depressions in the ground. For more information on glacial formations, see the links below, which will connect you to some sites with photos and descriptions.

There are two main types of glaciers — valley and continental. Valley or alpine glaciers form in mountainous regions where movement is inhibited by valley walls. Continental glaciers, also known as ice sheets, are "dome-shaped mass[es] of glacier ice… greater than 50,000 square kilometers (12 million acres) (e.g., the Greenland and Antarctic ice sheets)" (NSICD).

	Latest Monthly Climate Trends

		Departure of temperature from average for last month (updated by the 17th of each month) from the National Climatic Data Center.
		Average June arctic sea ice coverage as observed by satellites between 1979 and 2008. Image credit: National Snow and Ice Data Center.

Monthly Summary (Updated between the 16th and 19th of each month)

June 2008

June 2008 was the 8th warmest June for the the globe on record, according to statistics released by the National Climatic Data Center. The period January through June was the ninth warmest such period on record. La Niña ended in June, and neutral conditions now prevail in the tropical Eastern Pacific. For the contiguous U.S., June was the 27th warmest June since 1895. New Jersey and Rhode Island ranked second warmest and Delaware ranked third warmest. Iowa had its 2nd wettest June on record, which led to record flooding. Over the past six months, Iowa, Ohio, and Missouri had the wettest January-June on record. Iowa had its wettest April-June period on record with an average of 20.4 inches of precipitation - 8.7 inches above average. Five states (California, Georgia, Tennessee, and the Carolinas) were much drier than average, with California having the fourth driest June on record and North Carolina ranking eighth driest. Dry conditions set the stage for increased fire potential across the western U.S. By the end of June, many large wildfires were raging in northern California and Arizona, largely due to lightning strikes. As of June 30, more than 2.1 million acres have burned so far this year in the United States, according to the National Interagency Fire Center. Already, January - June 2008 ranks third behind the same periods for 2006 and 2002 in the amount of burnt acreage.

Sea ice extent

June 2008 Northern Hemisphere sea ice extent was the third lowest on record for the month of June, 6% below its extent in 1979 when satellite measurements began, according to the National Snow and Ice Data Center. June was the seventh straight month that a new monthly minimum arctic sea ice record was not set, following a string of five months in a row where monthly records were set. However, June 2008 ice extent was lower than in June 2007, and the stage is set for an all-time record Arctic sea ice loss this summer.

Climate Change Blogs:

Heat Waves (3): Role of Global Warming

Featuring Dr. Ricky Rood

Heat Waves (3): Role of Global Warming: In the last two blogs I talked about heat waves. I use heat waves as an example of the relationship of a “societal impact” sensitive to climate change. The impact of environmental heat on humans is a problem that has been around forever. It depends not only on how hot it is, but also the characteristics of the built environment (is the pavement black?), and the ability of a person to respond to the high heat (can you co...

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The tornado season of 2008: climate change to blame?

Featuring Dr. Jeff Masters

Let's be clear that human-caused climate change is occurring, and will significantly affect nearly all aspects of weather and climate in the decades to come. However, many of these changes will be so small or gradual that they will not become detectable until many decades hence, since there is a large natural variability in weather. As I noted in my February blog, Are tornadoes getting stronger and more frequent?, there is new research that predicts that we may see an increase in the severe thunderstorms that spawn tornadoes by the end of the century.

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	Iconic Image Gallery

The Iconic Image Gallery is a collection of figures that show important climactic trends. Click on each for a full-sized version of the image, the message that it contains, and a discussion of what makes it 'iconic'. Keep checking back -- we'll be posting additional images soon!


Keeling CO2	Vostok ice cores

Mitigation and Adaptation	Forcing

The Cryosphere: Snow and Ice